The invention relates to temperature changing devices and in particular to disposable beverage coolers and warmers.
A variety of foods and beverages require cooling only before consumption. For example, soft drinks in sealed bottles or cans can be stored indefinitely at average ambient temperature of 20.degree.-25.degree. C., but are preferably consumed only after their temperature is lowered to 5.degree.-10.degree. C. This has been usually accomplished by the utilization of ice cubes as rapid disposable cooling agents. The utilization of ice as cooling agent suffers from the fact that the ice has a limited life span at above freezing ambient temperature. The ice cubes may, therefore, not be available when the cooling action is required. This is especially likely to occur when the beverages are consumed in cars, beaches or picnic areas. One of the main objectives of the present device is to provide a rapid cooling device which can be stored for unlimited periods without losing its cooling potential.
The invention utilizes water as a cheap and disposable working liquid. It exploits the fact that the boiling point of a liquid is lowered by a vacuum. In the invention water boils in an air-evacuated sealed chamber and absorbs heat from its environment. To prevent the development of a vapor back pressure in the sealed container, which would stop the boiling of the water, the vapor generated by the boiling water must be continuously removed from the sealed chamber. This must be done without an opening in the chamber which would allow outside air into the chamber. In the present invention this is accomplished through the action of a dessicant kept in a separate air-evacuated container. A tube which can be opened and closed communicates between the dessicant and water chambers. When the communication between the water and the dessicant chambers is open, the dessicant absorbs the vapor generated by the boiling water. This prevents the vapors from exerting a counter-pressure upon the boiling water, and allows the water to boil until its temperature is lowered to its relatively low vacuum-boiling point temperature. When the communication between the water-chamber and the dessicant-chamber is closed, the vapor accumulates in the water-chamber and stops the boiling of the water. This is utilized as means for obtaining an unlimited storage of the device without loss of its cooling potential.
An additional objective of the invention is to provide physical means for warming of an object. This can be achieved by the fact that when the vapor is absorbed by a dessicant, heat of absorption is generated. Experimental studies of a model of the invention have shown that this raises the temperature of the dessicant to a temperature which is higher than the original ambient temperatures of both the water and the dessicant. The relatively warm dessicant can then transfer its heat to any desired object, such as a cold car engine or a bottle of milk for a nursing baby.
Other objectives of the invention will become evident during the full description of the invention in the Detailed Description Section.